This invention relates to compositions for the treatment of keratinous tissues, such as human fingernails and toenails, and for softening cuticles. It is particularly concerned with the provision of an improved composition for treating and maintaining nails in a supple, healthy condition. The human nail comprises structural protein, or scleroprotein, which is hard and insoluble and is made up of keratine. In addition to its inherent hardness, the human nail often becomes dry and brittle and subject to breaking, cracking or splitting. A nail conditioning composition which substantially overcomes such cosmetic problems is herewith provided.